1. Field of the Invention
The present invention relates to a treatment device for heating or cooling an object of treatment placed on a table.
2. Description of the Related Art
Generally, in manufacturing processes for semiconductor devices or LCDs, a series of treatments is carried out such that a photoresist is applied to a silicon substrate or LCD substrate (glass substrate), circuit patterns or the like are reduced and transferred to the photoresist by photolithography, and the transferred patterns are developed.
In these treatment processes, a heat treatment device is used to heat the substrate to pre-bake or post-bake it before or after the application of the resist solution. As shown in FIG. 1 or 2, for example, the principal part of this heat treatment device 52 is composed of a hot plate 60, a heating element 62, a cover member 66, and support pins 70. The plate 60 serves as a table which carries a substrate G thereon. The heating element 62 contains a heater which supplies heat to the substrate G through the hot plate 60. The cover member 66 is located so as to define a treatment space 64 over the substrate G. Gas produced during the heat treatment is discharged from the inside of the member 66. The support pins 70 penetrate their corresponding through holes 68 in the hot plate 60 and the heating element 62, whereby the substrate G is delivered over the plate 60. In the heat treatment device 52 shown in FIG. 1, the support pins 70 are fixed, and the hot plate 60 and the heating element 62 are allowed to move by means of a piston 74 of a lift cylinder 72, so that the pins 70 project and recede from the plate 60. In the heat treatment device 52 shown in FIG. 2, on the other hand, the hot plate 60 and the heating element 62 are fixed, and the support pins 70 are connected to a piston 78 of a cylinder 76 so that it can project and recede from the plate 60. In FIG. 2, a cylindrical shutter 80 is liftably arranged around the hot plate 60. The shutter 80 is connected to a piston 84 of a shutter lift cylinder 82 so that the capacity of the treatment space 64 can be adjusted by moving the shutter 80 up and down.
In the conventional heat treatment devices of this type, however, the hot plate 60 and the heating element 62 are formed integrally with each other, so that replacement of the plate 6C for cleaning operation or change of the substrate size is troublesome, and the maintenance efficiency is poor.
In order to solve this problem, there have been proposed a heat treatment device in which the hot plate 60 and the heating element 62 are separated from each other and a substance with high thermal conductivity is interposed between the two to secure heat transfer from the element 62 to the plate 60 (see Jpn. UM Appln. KOKAI Publication No. 57-84738) and one in which a spiral sheathed heater is provided under the hot plate 60 (see Jpn. UM Appln. KOKAI Publication No. 62-5638). In either case, the hot plate 60 and the heating element 62 are not in contact with each other, so that it is difficult to heat the whole hot plate 60 uniformly. When the substrate G is heated by means of the hot plate 60, uniformity cannot be secured for the temperature distribution of treatment heat.